1. Field of the Invention
The present invention relates to a toner containing, as a dispersant of a phthalocyanine pigment, a compound having an azo skeleton, the toner being used in electrophotography, electrostatic recording, electrostatic printing, or toner-jet recording.
2. Description of the Related Art
Insufficient dispersibility of a pigment in toner particles causes a decrease in the coloring power of the toner particles. To solve this problem, various techniques for dispersing a pigment have been developed.
Regarding a technique for dispersing a phthalocyanine pigment in a toner, for example, Japanese Patent Laid-Open No. 03-113462 discloses that a polymer containing sodium styrenesulfonate as a monomer unit is used as a dispersant. As another example, a method has also been proposed in which dispersibility of a phthalocyanine pigment is improved by allowing metal-containing phthalocyanine and a polymer having a substituent that can be coordinated with the metal-containing phthalocyanine (hereinafter abbreviated as “coordinating polymer”) to coexist.
For example, Japanese Patent Laid-Open No. 2003-277643 discloses that a 4-vinyl pyridine/styrene copolymer is used as the coordinating polymer. Japanese Patent No. 4510687 discloses that a copolymer of styrene and a monomer having an amide group is used as the coordinating polymer.